Numerous situations exist in which interior parts of the human body needs to be catheterized through an artificial stoma to achieve a desired medical goal. Relatively common situations are for drainage of retained fluids and administering nutritional solutions or medicines directly into the stomach or intestines. For these situations a stoma is formed percutaneously and an indwelling device is placed through the stoma. By way of example the surgical opening and/or the procedure to create a stoma spanning between the stomach or intestinal wall and the exterior of the skin is commonly referred to as “gastrostomy”. A device with a catheter component, e.g. a feed tube, placed through such a stoma allows injection of feeding solutions through the tube to provide nutrients directly to the stomach or intestines (known as enteral feeding). A variety of different devices intended for enteral feeding have been developed over the years, including some having a “low profile” relative to that portion which sits on a patient's skin, as well as those having the more traditional or non-low profile configuration. These percutaneous transconduit devices (sometimes referred to as “percutaneous transconduit catheters”) are frequently referred to as “gastrostomy tubes”, “percutaneous gastrostomy tubes”, “PEG tubes” or “enteral feeding tubes”. U.S. Pat. No. 6,019,746 for a “Low Profile Balloon Feeding Device” issued to Picha et al. on Feb. 1, 2000, provides an example of one device.
Such devices have a head portion (sometimes referred to as a “base”) that resides outside of the patient and sits on the patient's skin. To prevent the device from being pulled out of the stoma, various types of retainers are used at a distal end of the device and reside inside the patient. Examples of conventional devices with Malecot tips or similar expanding tips as retainers are found at, for example, U.S. Pat. No. 3,915,171 for “Gastrostomy Tube” issued to Shermeta; U.S. Pat. No. 4,315,513 for “Gastrostomy and Other Percutaneous Transport Tubes” issued to Nawash et al.; U.S. Pat. No. 4,944,732 for “Gastrostomy Port” issued to Russo; and U.S. Pat. No. 5,484,420 for “Retention Bolsters for Percutaneous Catheters” issued to Russo. Exemplary commercial products with head portions and retainer portions include the Passport® Low Profile Gastrostomy Device available from Cook Medical, Inc. of Bloomington, Ind. and the Mini One™ Non-Balloon Button available from Applied Medical Technology, Inc. of Brecksville, Ohio.
One frequent problem with these devices is that during initial placement, the physician may be too aggressive in applying pressure when seating the retainer. This will result in the distance between the head and the retainer being too short for the length of the stoma. As a result, the stoma tract will be squeezed between the head and the retainer causing discomfort and pain for the patient.
Another frequent problem with these devices is that the length of the stoma tract itself may change over time due to feeding and nutrition uptake. For example, weight gain by a patient may result in an increase in the thickness of tissue between the head and retainer. This additional tissue can push axially against the head and the retainer causing discomfort and pain for the patient. Alternatively and/or additionally, inflammation or infection of tissue around the stoma site may cause swelling between the head and the retainer of the tube. The swelling tissue can push axially against the head and the retainer causing discomfort and pain for the patient. On the other hand, weight loss by a patient may result in a decrease in the thickness of tissue between the head and retainer and, after a proper initial placement, cause the head and the retainer to fit too loosely causing leakage or movement of the device.
Accordingly, there is a need for an indicator assembly for devices with catheter, head and retainer components that can signal changes in the axial length of the stoma tract. There is also a need for an indwelling catheter device that incorporates such indicator assembly. A need also exists for an initial positioning system that can provide a signal to a physician that the proper axial length of the retention system of an indwelling catheter device has been reached. There is a need for a repositionable indicator system that provides a signal indicating proper axial positioning of the retention system of an indwelling catheter device (e.g. an enteral feeding tube or other catheter tube).